Electronic tuner

ABSTRACT

An electronic tuner in which a resonant frequency is changed by changing the voltage applied to a variable tuning element, and in which there is provided a base metal, on the face and back of which are attached a band change-over switch base plate and a resonant voltage change-over switch base plate respectively, these base plates are provided with a rotary switch rotating on the base plates, and the rotary switch is rotated by means of a push button, an electro-magnet or motor.

United States Patent [191 Yokoyama et al.

[ Aug. 6, 1974 3,525,824 8/1970 Von Fange et al. 200/11 D 3,654,413 4/1972 Jordan et al. 200/156 3,662,295 5/1972 Rummer 334/7 6/1973 Kimura et al. 334/9 Primary Examiner-Paul L. Gensler Attorney, Agent, or Firm-Craig & Antonelli [57] ABSTRACT An electronic tuner in which a resonant frequency is changed by changing the voltage applied to a variable tuning element, and in which there is provided a base metal, on the face and back of which are attached a band change-over switch base plate and a resonant voltage change-over switch base plate respectively, these base plates are provided with a rotary switch rotating on the base plates, and the rotary switch is rotated by means of a push button, an electromagnet or motor.

I 4 Claims, 22 Drawing Figures ELECTRONIC TUNER [75] Inventors: Kanji Yokoyama; Hiroshi Miwa,

both of Yokohama, Japan [73] Assignce: Hitachi, Ltd., Tokyo, Japan [22] Filed: Dec. 5, 1972 [21] Appl. No.: 312,288

[30] v Foreign Application Priority Data Dec. 6, 1971 Japan 46-97871 [52] US. Cl. 334/14, 74/10.15, 200/11 DA, 334/7, 334/15, 334/8, 334/87 [51] Int. Cl. H03j 5/04 [58] Field of Search 334/7-10, 14, 334/15, 17, 47, 86, 87; 200/11 D, 156, 11 DA; 325/422, 459, 464, 468; 74/10 R, 10.1, 10.15, 10.9; 323/80, 94

[56] References Cited UNITED STATES PATENTS 3,303,3l1 2/1967 Streuer 200/156 Q g l 11 {I III].

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LEFT RIGHT ELECTRONIC TUNER FIELD OF THE INVENTION This invention relates to an electronic tuner or more in particular to an electronic tuner for use with a television receiver which is capable of selecting a desired channel by switching a source voltage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a channel-selecting system of the most commonly used prior art electronic tuner.

FIG. 2 is a diagram showing a sectional view taken in the line IIII of FIG. 1.

FIG. 3 is a front view of a dial used with the electronic tuner of FIG. 1.

FIG. 4 is a diagram showing another example of the front view of the channel-selecting system of the conventional electronic tuner.

FIG. 5 is a partly broken front view of the electronic tuner embodying the present invention.

FIG. 6 is a side view of the embodiment of FIG. 5.

FIGS. 7a to 7d are diagrams showing developments of the electronic tuner of FIG. 5.

FIG. 8 is a disassembled perspective view of the essential parts of the electronic tuner shown in FIG. 5.

FIG. 9 is a diagram showing a section of the rotary switch used in the electronic tuner according to the present invention.

FIG. 10 is a diagram showing the manner in which the tuner shown in FIG. 5 is mounted on the television cabinet.

FIG. 11 is a perspective view of the essential parts of the electronic tuner of FIG. 5.

FIGS. 12 and 13 are front and side views of another embodiment of the present invention.

FIGS. 14 and 15 are front and side views of still another embodiment of the invention.

FIGS. 16 and 17 are front and side views of still another embodiment of the invention.

FIGS. 18 and 19 are front and side views of still another embodiment of the invention.

DESCRIPTION OF THE PRIOR ART The operating requirements of a channel-selecting system of the electronic tuner for use with the television receiver are:

I. that the electronic tuner is capable of being supplied with a given analog resonant voltage (usually a DC voltage of 0 to 30 volts) 2. that each button or key is provided with a corresponding definite channel display system. In other words, a channel at which each button is preset is capable of being easily identified.

3. that the electronic tuner is provided with a band change-over switch for electronically switching a number of channels into which a wide frequency band is divided.

4. that a button which corresponds to a channel selected is capable of being identified among, if any, a plurality of buttons.

The manner in which a resonant voltage is obtained will be explained below with reference to FIG. 2.

The reference numeral 1 shows a shaft for fine adjustment and numeral 2 a middle shaft both of which constitute a channel-selecting button. The middle shaft 2 is locked with a slide cam 3 by pressing the shaft 1. At the same time, a clutch 4 provided on the inner wall of the shaft 1 engages a clutch 6 of a bevel gear 5, so as to rotate the fine adjustment shaft 1 thereby to rotate a volume shaft 8 through a bevel gear 5 and a bevel gear 7. A thread 9 is cut over the entire surface of the volume shaft 8, which thread is fitted with a sliding contact 11 with a reaction force applied from a resistance base plate 12, the sliding contact 11 being supported by a supporting means 10. As a result, one rotation of the volume shaft 8 causes the sliding contact 11 to move in the axial direction in the thread 9 on the resistance base plate 12, thereby making it possible to obtain a resonant voltage.

A selected channel is displayed on a dial 14 by means of a pointer 13 provided on the sliding contact supporter 10. The channel numbers at the ends of each band selected are displayed on the dial 14 as shown in FIG. 3, so that a desired band is displayed in a window 16 of a front plate 15.

In switching the bands, the fine adjustment shaft 1 is pulled up so that a clutch pawl 19 arranged on a driving member 18 engages a clutch pawl 17 on the fine adjustment shaft 1, thereby to rotate the fine adjustment shaft 1 and the driving member 18 supported on the middle shaft 2. By the use of the driving member 18 which is intermittently rotated in a desired number of steps, band change-over switches 20 and 21 are driven through an intermittently rotating driving knob 18'. The band change-over switch 21 is supported on a supporting means 22 which is provided with stepped protrusions in the direction of the stroke of the middle shaft 2 thereby to urge the rotation of the band changeover switch 21 in accordance with a desired band as shown by the dashed line of FIG. 2. Display of the channel corresponding to a desired band is effected by intermittently sliding the dial 14 by means of a pawl 23 provided on the driving member 18. This method does not employ any matching between the selected channel and the corresponding button.

The above-mentioned conventional electronic tuner has the following disadvantages:

l. The characters engraved on the dial 14 which in cooperation with the pointer 13 on the sliding contact supporter 10 effects channel display are so small that it is difficult to identify them at a distance from the television set or in darkness.

2. It is impossible to engrave on the dial 14 the figures of all the channels within the band involved. When the band is divided into three, for example, as shown in FIG. 3, the numbers of the channels only at the center and the ends of the UHF band are engraved, thereby making the pointer 13 unable to indicate an exact channel number.

' A conventional method of overcoming these disadvantages consists of one in which, as shown in FIG. 4, given preset number plates 24 are attached onto the side of each button. Even in this method, however, the only clue for identifying a button selected for operation is the retreat of the fine adjustment shaft 1 by 2 to 4 mm through the bush stroke, and therefore the identification of the channel number is almost impossible when viewed from the front or from a point at a distance or in the dark.

Another well-known method in an effort to obviate this shortcoming is one in which a lamp and an ON- OFF switch for the operation therefor are provided for SUMMARY OF THE INVENTION The present invention provides an electronic tuner in which a resonant frequency is changed by changing the voltage applied to a variable tuning element, characterized in that a rotary switch by means of which the voltage applied to the variable tuning element is changed is driven at the press of a push button or similar means.

An object of the invention is to provide a unique electronic tuner for the television receiver which obviates the disadvantages of the conventional electroni tuner.

Another object of the present invention is to provide a low-cost electronic tuner with a simple construction.

Still another object of the invention is to provide an electronic tuner in which provision of a rotary switch facilitates the operation of a channel-selecting system.

Still another object of the invention is to provide a display unit which is capable of illuminating and displaying a selected channel in a large character with a 7 single lamp.

,Wtill another object of the invention is to provide an electronic tuner which is easily capable of remote control in cooperation with a remote control means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Differing from the conventional electronic tuner in which a button corresponding to a desired channel among a certain number of buttons equal to the number of broadcasting stations is pushed for channel selection, the electronic tuner according to the invention is of a rotary type in which a ratchet is driven through a ratchet driver by pushing, say, two buttons whereby a rotary switch is rotated to the right or left for channel selection.

The electronic tuner according to the present invention will be now explained in detail with reference to the accompanying drawings.

The reference numeral in FIG. 5 shows an electronic tuner proper, and numeral 26 in FIG. 6 a printing base plate proper comprising, as shown in FIGS. 7a to 7d, a base metal 28 made of a rigid and unwarped steel plate, a band change-over switch base plate 29 and a resonant voltage change-over switch base plate 30 with printed circuits on the face and back of the base metal 28 respectively, and a resistance base plate 34 printed with resistors 33 and provided with slits 32 for receiving a band change-over switch pattern 31, the resistance base plate 34 being laid over the band change-over switch base plate 29. The band changeover switch base plate 29, as shown in FIG. 7b, includes the band change-over switch pattern 31 representing the three divisions of the band, that is, two divisions of the VHF band and a division of the UHF band, the reference numerals 311, 312 and 313 indicating patterns which represent channels 2 to 6 at the lower level of the VHF band, channels 7 to 13 at the higher level of the VHF band and channels 14 to 83 of the UHF band respectively.

The reference numeral 35 shows a front panel provided on that side of the printing base plate proper 26 which is nearer to the resistance base plate 34, which front panel including eight sets of windows, each set having 5 windows 351, 352, 353 and 53, while on the side of the front panel 35 is bored eight holes 354, as shown in FIG. 8.This front panel supports eight sets of component elements, each set comprising a fine adjustment knob 39, volume shaft 36, sliding contact supporting means 40 and a band change-over contactsupporting means 43. A thread 361 is cut on the volume shaft 36 and a volume gear 37 is mounted on the end of the volume shaft 36. The reference v numeral 39 shows a fine adjustment knob including a gear 391. The volume shaft 36 is inserted into the aperture 354 of the front panel 35 and supported by the front panel 35 with a U-shaped spring 50. The fine adjustment knob 39 engages the'gear 37 of the volume shaft 36, while being slightly protruded from the window 3510f the front panel 35. The fine adjustment knob 39 is supported accurately by inserting thereinto a supporting shaft 38, whereby the rotation of the fine adjustment knob 39 is imparted to the volume shaft 36. The reference numeral 40 shows the sliding contact supporting means including a protrusion 54 and a recess 401 on which the sliding contact 41 is mounted. The volume shaft 36 en- 'gages the recess 401 as a result of causing the sliding contact 41 fixed on the supporting means 40 to engage the thread 361 of the volume shaft 36. The sliding contact 41 slides over the resistor 33 of the resistance base plate 34 in response to the rotation of the volume shaft 36. As a result, the rotation of the fine adjustment knob 39 does not result in the rotation of the sliding contact supporting means 40 but causes it to move in a sraight line. This movement is displayed by means of the protrusion 54 projected from the window 53 of the front panel 35. Also, the front panel supports the band change-over contact supporting means 43 with a dial 42 in such a manner that the protrusion 431 of the band change-over contact supporting means 43 is projected from the window 352, whereby the character displayed on the dial 42 can be viewed from the window 353. The

characters 2, 7, 14, 6, l3 and 83 are engraved on the dial 42, and either of the three pairs of the characters, i.e., 2-6, 7-13 or 14-83 appears on the window 353. When the character pair of 2 and 6 is indicated on the window 353, for example, it means that any of VHF channels including channels 2 to 6 can be selected, if the FIGS. 7 and 13 are indicated, it means that any of VHF channels including channels 7 to 13 can be selected, and if the FIGS. 14 and 83 appear it indicates that the tuner is ready for reception of the UHF band.

The band change-over contact supporting means 43 is provided with a band change-over contact spring 44. The sliding contact 41 of the sliding contact supporting means 40 is slidably coupled with the resistor 33 of the resistance base plate 34, while the band change-over contact spring 44 of the band change-over contact supporting means 43 is connected through the slit 32 of the resistance base plate 34 to the band change-over switching pattern 31 of the band change-over switch base plate 29. The band change-over contact spring 44 is such that a contacted pattern changes as the protrusion 431 of the band change-over contact supporting means 43 is moved to the right or left.

The U-shaped spring 50 for supporting the volume shaft 36 is connected, through the resistance base plate 34 and the band change-over switch base plate 29, to the terminal 301 of the resonant voltage change-over switch base plate 30.

The reference numerals 47 and 48 show rotors supporting a resonant voltage change-over contact spring 45 and a band change-over sliding contact 46 respectively, which rotors are mounted springingly on both sides of the printing base plate proper 26 is such a manner that elastic molded hooks 49 provided on the supporting rotor 47 are replaceably inserted into the holes 291 and 302 of the printing base plate proper 26, as shown in FIG. 9, thereby to engage the supporting rotor 48. As will be apparent from FIG. 9, a rotary switch proper 91 comprises the supporting rotors 47 and 48, the resonant voltage change-over contact spring 45 and the band change-over sliding contact 46, the base metal 28, the band change-over switch base plate 29 and the resonant voltage change-over switch plate 30. A source voltage applied across the resistor 33 of the resistance base plate 34 is divided as desired by the sliding contact 41 and each of the resulting resonant voltages is introduced, through the volume shaft 36 and the U-shaped spring 50, to the input terminal 301 of the resonant voltage change-over switch base plate 30, so that it is obtained at an output terminal 303 by means of a rotary switch pattern 51. At this time, the volume shaft 36 is electrically connected with the sliding contact 41 upon the feeding of the contact 41 in the axial direction, and therefore the voltage across-the volume shaft 36 changes as it moves in the axial direction. The amount of feed in the axial direction, that is to say, the value of the resonant voltage is indicated by the protrusion 54 on the sliding contact supporting means 40 which is projected through the window 53 on the front panel 35.

The operation of band change-over is effected by sliding intermittently the band change-over contact supporting means 43 in the window 352 of the front panel 35. In other words, the band change-over contact spring 44 which operates out ofthe band change-over contact supporting means 43 slides over the band change-over switch pattern 31 of the band change-over switch base plate 29 for desired pattern connection. The pattern 52 of the band change-over switch base plate 29 is formed on a side opposite to the rotary switch pattern 51 for switching resonant voltages. Under this condition, the channel number of a desired band on the dial 42 which integrally moves with the band change-over contact supporting means 43 is indicated through the window 353 on the front panel 35.

It will be apparent from the above explanation how the resonant voltage generating portion and the band change-over portion work, and the whole system of the device according to the invention will be easily understood by explaining the system for rotating to the right or left the rotary switches for the change-over of the resonant voltage or the band which are integrated with each other.

In FIG. 6, the reference numeral 27 shows a ratchet comprising, as shown in FIG. 11, two engaging members 271 and 272 arranged on the opposite sides of a gear-like portion 273, the upper and lower engaging members 272 and 271 being threaded in such a manner as to rotate in the left and right directions respectively. The rotation of the ratchet 27 causes the switching of a resonant voltage and channel to be effected, the ratchet 27 being fixed on a gear shaft 65 by means of a supporting metal 63. The gear shaft 65 is provided with a bevel gear 651 and a channel indicating drum 67 is fixed on a boss 66 with a screw 68 and a stop protrusion 69. The reference numeral 70 shows a rotary shaft for the supporting rotors 47 and 48, and a bevel gear 701 on the rotary shaft 70 engages the bevel gear 651 mounted on the shaft 65. The rotary shaft 70 is supportingly fixed on the supporting metal 63 by means of an E-ring 71 and rotated by the gear shaft 65.

The numerals 72 and 73 shows push shafts slidably supported on the supporting metal 63. The removal of the push shafts 72 and 73 is prevented by the insertion of compression springs 74 and 75 between the supporting metal 63 and stoppers 76 and 77. The push shafts 72 and 73 are provided with driver portions and 81 for pushing ratchet drivers 57 and 58 and are supported on the supporting metal 63 through holes 78 and 79 cut in the band change-over switch base plate 29 and base metal 28 and the resonant voltage changeover switch base plate 30.

The reference numerals 57 and 58 show the ratchet drivers one end of each of which is fitted in the push shafts 72 and 73, while the other ends thereof are attached to a supporting metal 55 through tension springs 59 and 60. The ratchet drivers 57 and 58 have one end brought up to the side of the drivers 80 and 81 of the push shafts 57 and 58 by means of the tension springs 59 and 60 with the end 56 of the supporting metal 55 as a supporting point. Also, on the ends of the ratchet drivers 57 and 58 are formed, as shown in FIG. 11, hooks 61 and 62 for engaging the lower and upper engaging members 271 and 272, respectively. The reference numerals 571 and 581 show recesses formed in the ratchet drivers 57 and 58 and in which the push shafts 72 and 73 are fitted.

The manner in which the ratchet 27 is driven is shown in detail in FIG. 11. By pushing the push shaft 72 fitted in the recess 571 of the ratchet driver 57, the ratchet driver 57 is pressed by the driver 80, whereby the hook 61 of the ratchet driver 57 engages the engaging member 271 of the ratchet 27 thereby to rotate the ratchet 27 in one direction. The pushing of the push shaft 73 fitted in the recess 581 of the ratchet driver 58 causes the driver 81 to press the ratchet driver 58, so that the hook 62 of the ratchet driver 58 engages the engaging member 272 of the ratchet 27 thereby to rotate the ratchet 27 in one direction. The accuracy with which the ratchet 27 is rotated in both directions is secured by a tension plate 64with a ball fitted therein.

The rotation of the ratchet 27 due to the pushing operation of the push shafts 72 and 73 is transmitted to the rotary switch proper 91 comprising the channel indicating drum 67, the supporting rotor 47 for the resonant voltage change-over switch base plate 30 and the supporting rotor 46 for the band change-over switch base plate 29, thereby achieving the synchronization between the rotations of the ratchet 27 and the rotary switch proper 91.

The reference numeral 83 in FlG. 6 shows a slit formed in the channel indicating drum 67, into which a plate indicating a desired channel number is inserted. The numeral 84 shows a lamp for illuminating the channel number, and numerals 85 and 86 show push buttons for pressing the push shafts 72 and 73 and mounted on a front panel 82.

With the above-mentioned construction of the tuner according to the present invention, the individual channels are selected and shown as follows. In each window group comprising the windows 53, 351, 352 and 353, the protrusion 431 projected'from the window 352'is adjusted so that each of switch contacts 292 (FIG. 7b) is selectively connected to one of the patterns 311, 312 and 313 in order to conduct a voltage applied to the selected pattern to the corresponding one of switch contacts 293. The voltage is to be applied to the variable tuning element for making it possible to receive channels belonging to band corresponding to the voltage. Then, the fine adjustment knob 39 projecting from the window 351 is adjusted so as to slide the sliding contact 41 on the resistor 33 so that a voltage to be ap-' contact 41, the volume shaft 36 the U-shaped spring 50 and the terminal 301 to the corresponding one of switch contacts 304 (FIG. 7d). The protrusion 431 and the knob 39 are thus adjusted and preset. In this manher, the switch contacts 293 are preset to respective voltages corresponding to desired bands and the switch contacts 304 are preset to' respective voltages corresponding to desired channels. ln this state, the push buttons 85 and 86 are operated so that the rotors 47 and 48 are rotated so as to selectively connect one of the switch contact 293 and one of the switch contacts 304 to a rotary contact 294 and a rotary contact 305 respectively. Therefore, the voltages preset to the selected switch contacts are applied to the variable tuning element through the rotors 47 and 48, the rotary contacts 294 and 305 and the output terminals 303 so that a desired channel is selected. Simultaneously with the rotation of the rotors, the drum 67 isrotated and the channel number plate corresponding to the selected channel inserted into the slit 83 is caused to appear on the front of the tuner so as to indicate the selected channel. i

Front and side views of another embodiment of the present invention are shown'in FIGS. 12 and 13 respectively. In the figures, it will be seen that only one engaging member of the ratchet 27 associated with a single rotational direction is provided so as to limit the rotation of the ratchet 27 in a single direction for channel switching. As a result, as can be seen from the drawing, the present embodiment comprises a single unit of each of the push button 85, the push shaft 73 pressed by a push button 85 and the ratchet driver 58 which rotates the ratchet 27, whereby endless rotation is achieved of the supporting rotor 48 of the resonant voltage changeover switch base plate 30, the supporting rotor 47 of the band change-over switch base plate 29 and the channel indicating drum 67.

Front and side views of still another example of the electronic tuner embodying the present invention are shown in FIGS. 14 and 15. In the figures, the rotation of the ratchet 27 is seento be effected not by the push shaft but by electromagnets 87 and 88.

The operation of this embodiment will be explained with reference to the drawings. The electromagnets 87 and 88 are mounted on the supporting metal 55, while push buttons 89 and for actuating the electromagnets 87 and 88 are connected with switches SW, and SW on' the front panel 82. The switch SW, is closed at the press of the push button 89 whereby. the ratchet driver 57 is attracted "to the 'electromagnet 87 thereby to rotate the ratchet 27 in the right direction. The subsequent operations are the'same as in the embodiment of FIG. 6. The pressing of the left button 90 causes the switchSW to be closed so that the electromagnet 88 is energized to attract the ratchet driver 58 thereto, followed by the same operations as those inthe embodiment of FIG. 6. In the present embodiment, remote control is possible instead of the manual operation which is effected with the push buttons 89 and 90. In this connection, the reference numeral 106 shows a remote control receiver and numeral 107 a transmitter.

'When a remote control system is employed in the invention, it will be noted from FIG. 15 that one of the two terminals of each electromagnet is grounded and the other is connected with the remote control transmitter, so that switches SW, and SW' are energized by switches SW, and SW", in the remote control transmitter and DC voltage B is applied to the electromagnets thereby enablingany of the right and left electromagnets to be energized.

Incidentally, in case where the manual switches SW, and SW and the remote control switches SW", and SW, operate at the same'time, a priority of operation may be obtained by the manual switches SW, and SW Although the embodiment of FIGS. '14 and 15 may be used independently as explained above, it is apparent that the remote control system according to the invention'may also be embodied in combination with the other embodiments as will be seen from the electromagnet which is shown by a dashed line and marked with a referencenumeral 110 in the embodiment of FIGS. '12 and 13 and that of FIGS. 16 and 17 which will be described later.

FIGS. 16 and 17 show the front and side views of still another embodiment of the invention. In this embodiment, along cylinder-shaped channel indicating drum 111 is mounted on the side of the front panel 35. On the outer cylindrical surface of the drum 111, a plurality of channel indicating members 111,, 111 111 are provided, which are red-painted for example. The drum 111 has a gear 201 engaged with an idler gear 202. Through this idler gear 202, the gear 201 is coupled with a gear 92 provided on the shaft 65. Therefore, the rotation of ratchet 27 can be transmitted through the bevel gears 701 and 651, the gear 92 and the idler gear 202 so that the channel indicating drum 111 rotates simultaneously with the rotation of the ratchet 27 and the rotors 47 and 48. The gear 201 has the same diameter and number of teeth as the gear 92. Therefore, when the gear 92 rotates by one tooth, the gear 201 also rotates by one tooth, so that the drum 111 rotates by an extent corresponding to one channel.

The front and side views of still another embodiment of the invention are shown in FIGS. 18 and 19. In this embodiment, a motor is employed as a source for driving the rotary switch, so that the continuous rotation of the motor is converted into the intermittent rotation thereof by the use of a Geneva stop system thereby to achieve the intermittent rotation of the rotary switch.

The operation of the embodiment will be now explained with reference to the drawings. The high speed rotation (3,000 to 4,000 rpm) of the micro-motor is transmitted through a coupler 94 to a pinion gear 95, and then it is reduced to a desired level of 100 rpm by several small and large gears 96. Since the pin 98 of a Geneva stop 97 is formed in a Geneva gear 99 fixed on the shaft 65 and which is fitted in one of grooves 100 in the number corresponding to the number of the.

available channels, the rotation of the Geneva stop 97 is transmitted to the Geneva gear 99. Therefore, although the Geneva stop 97 rotates continuously, the Geneva gear 99 is intermittently rotated due to the fact that a steel ball 102 is pressed by a spring 103 against a detent cam 101 formed integrally with the pin 98 and Geneva gear 99. In this way, the intermittent rotation of the rotary switch and the channel indicating drum is attained. The forward and reverse rotation of a'motor 93 is effected by pressing push buttons 104 and 105 on the front panel 82. This embodiment is also adapted for use with a remote control by the provision of a remote control receiver 108 and a tramsmitter 109. In FIG. 19 which explains a remote control system used with the present embodiment, the remote control receiver is connected as shown so that electronic switches SW, and SW provided within the receiver are energized by remote control switches SW" and SW of the transmitter whereby a given DC voltage +B or B which is higher or lower than the earth potential is applied to the motor as desired to achieve forward and reverse rotations of the motor. In case where the manual switches SW, and SW and the remote control switches SW and SW" operate at the same time, a priority of operation may be obtained by the manual switches SW and SW In the channel indicating operation in the embodiments of FIGS. 12 to 15, the fact that the channel indicating drum 67 the rotation of which is synchronous with that of the ratchet 27 is mounted on the boss 66 of the gear shaft 65 permits the channel indicating drum 67 to rotate by the same angle as the rotational angle of the ratchet 27 in complete harmony with the depression of the push buttons 85 and 86 or 89 and 90. The same effect is achieved by the embodiment 1 of FIGS. 16 and 17 in which the channel indicating drum rotates in synchronism with the shaft 65 through a gearlike transmitter means even though the channel indicating drum is not mounted directly on the gear shaft 65. Also, in the channel indicating operation of the embodiment of FIGS. 18 and 19, the channel indicating drum rotates by the same angle as the angle of the groove 100 of the Geneva gear 99 in complete harmony with the depression of the switch 104 due to the fact that the channel indicating drum 67 which rotates in synchronism with the Geneva gear 99 is mounted on the boss 66 of the gear shaft 65. The channel indicating drum may be used for various numbers of channels by dividing the ratchet 27 and the Geneva gear 99 into a desired number of angles. If the ratchet 27 and the Geneva gear 99 are divided into 12 angular portions, the rotary switches are applicable to receiving 2, 3, 4, 6 or 12 stations (by shorting the change-over switches of the base plate corresponding to each of the numbers of the stations).

The electronic tuner according to the present invention may be exposed on the front panel of the television receiver. But for the purpose of design, there may be 89 and 90 and the switches 104 and 105 on the frontpanel 82 are detached from both the push shafts 72 and 73 and the electromagnets 87 and 88 so as to be movable in the direction of the axis of the push shafts. As a result, the push buttons 85, 86, 89 and 90 and the switches 104 and 105 remain attached to the front panel 82 as it is opened or closed.

The electronic tuner according to the present invention with the construction illustrated with reference to the embodiments above has the advantages:

1. that the fact that the channel indicating drum 67 rotates in synchronism with the rotary switch 91 for change-over of resonant voltage and band by driving the Geneva gear 99 or ratchet 27 permits not only accurate channel indication in a large character but illumination thereof with a single lamp 84.

For example, if the ratchet and Geneva gear are divided into 12 angular portions and the dial drum 67 is made mm in diameter and 40 mm in thickness, it is possible to display a channel number of a size at least 15 mm by 18 mm thus enabling it to be identified by a viewer at a considerably distant point.

2. that the channel-selection system in which the ratchet or Geneva gear is rotated to the right or left at the press of a push button obviates the difficulty of identification of a button corresponding to a channel selected.

3. that unlike the conventional electronic tuner in which resonant voltage change-over and band change-over switches are provided for each push button separately, all of such switches are concentrated at a point in the form of a rotary switch thereby simplifying the whole construction of the device and reducing the number of component elements sharply.

4. that the fact that the rotary switch 91 explained in 3 above is integrated with the band change-over switch base plate 29 and the resonant voltage change-over switch base plate 30 eliminates the need for the work of connecting the rotary switch 91 to a source of the resonant voltage and the band change-over voltage.

5. that even if excessive force is applied to the tuner when channel numbers are inserted in the channel indicating drum 67 on the shaft 65 of the ratchet 27, the stability of the rotary switch is not affected since the rotary switch system is provided separately from the shaft 65 of the ratchet 27.

6. that since the ratchet drivers 57 and 58 are actuated, for channel selection, by energizing the electromagnets 87 and 88 on the ratchet system at the press of separately provided push buttons 89 and 90, it is possible to locate the channel selection buttons (the same as push buttons 89 and at any desired positions and also remote control operation is facilitated in combination with a remote control system.

We claim:

1. An electronic tuner in which a resonant frequency is changed by changing a voltage applied to a variable tuning element; comprising:

a band change-over switch base plate consisting of an insulating plate" having a hole'ftherethrough and a 'first circular rotary contact arranged around the hole, aplurality of first switch contacts arranged around theperiphery of the first'rotary contact, a plurality of second switch contacts aligned in afirst direction with predetermined equal intervals .and electrically-connected to said first switch contacts, "respectively, and a plurality "of band contact 1 groups, each group including a, plurality" of band contacts electrically connected-with each other and supplied witha voltage and provided in cooperating relation with respective said'seco nd switch contacts,.the bandcontacts provided in cooperating relation with one of the second switch contacts to said first direction;

being aligned in' a second direction perpendicular 'a-resistance base plate. consistingiof an insulating plate having thereon-a pair of first terminal memj .bers extended in the same direction .as'said'fir'st direction, and .a plurality of resistor members ex} tended. in the same direction as said second, direction with the same intervals as 'said'predetermine'd intervals of said second switch contacts between,

the first terminal. members, :said. resistor members being'supplied with voltages throughsaidfirs't ter-.

'minal-members;

- consisting of an insulating plateYhaving a' h'ole therethrough and a second circular-rotary contact I arranged around the hole, a plurality of thirdswitch contacts arranged aroundthe periphery of the second circular'rotary contact, and aplurality of secondterminal members aligned in the same direction as said first directionwith the same inter.- vals as said predeterminedinterval's of said second switch contacts and electrically connected to said third switch contacts, respectively;

I 'a resonant voltage" change-over switch base plate 7 4 a plurality of band change-over switches provided for respective said second switch contacts, each for sev lectively connecting the corresponding second switch contact toone of the band contacts aligned .in the second direction incooperating relation with said corresponding second switch contact so as to conduct the voltage applied to said one of the band contacts .to the corresponding one of the first switchcontacts for band changing-over;

a' mounting-base, plate, having a hole therethrough 1 corresponding to the through-holes of said bandchange-over switch base plate and resonant voltage,

change-over switch base plate, for mounting on one surface thereof said band change-over switch base plate on which said resistance base plate is I n i e nd. onf h other;surfaceisaid resenant"'52.- I

voltage change-overswitch bes P te:

a plurality of slide members provided for respective. i i

said resistor members, each for taking out a predetermined voltage in accordance with the. position mined voltages to respective said third switch contacts;

-' a first rotary jswitch fixed to a'rotary shaftiinserted into said throughhcles,"for selectively connecting one of saidfirst switch contacts to said first-rotary contact so as to' derivefro'm the first rotary contact} said voltage conducted to "saidcne of the first switch contacts as a band change-over voltage to be applied to "the variabletuning-element;

a second rotary switch, fixed tosaid rotaryshafh'for] selectively. connecting one of said third switch contacts to-said second rotary contact so as to'd'erive from the sewed t yl nt cr said Predeteri ned'voltage conducted totsaid: one of th third switch contacts as aresonant voltage to". be. applied to the variable tuning element for tuning;and 3 driving means manually operable for driving said first and second rotary switches ina rotary movement for said selective connection.

2. An electronic tuner according to claim l,wherein- I said slide member comprises-a threadedshaft and. a slide contact supported on the shaftan'd movable on the shaft in accordance with the rotation of the shaft,-

and said connecting means comprises a U-shaped metal plate one end of which is fixed to said 'second'terminal member and which is capable of rotatably supporting one end of the shaft at the bottom of the'U-shape.

3. An electronic tuner according to claim 1, wherein said insulating plate of said resistance base plate is pro- 7 vided with a plurality of slits for exposing said 'band contacts and second switch contacts for allowing said selective connections by said band change-over I switches through said slits.

4. An electronictuner according to claim 1, wherein said driving means comprises at least one operation shaftmovable along the axis thereof, a ratchet rotating in accordance with the movement in one direction of the operation shaft, and means for rotating said rotary shaft in accordance with the rotation of said ratchet. 

1. An electronic tuner in which a resonant frequency is changed by changing a voltage applied to a variable tuning element; comprising: a band change-over switch base plate consisting of an insulating plate having a hole therethrough and a first circular rotary contact arranged around the hole, a plurality of first switch contacts arranged around the periphery of the first rotary contact, a plurality of second switch contacts aligned in a first direction with predetermined equal intervals and electrically connected to said first switch contacts, respectively, and a plurality of band contact groups, each group including a plurality of band contacts electrically connected with each other and supplied with a voltage and provided in cooperating relation with respective said second switch contacts, the band contacts provided in cooperating relation with one of the second switch contacts being aligned in a second direction perpendicular to said first direction; a resistance base plate consisting of an insulating plate having thereon a pair of first terminal members extended in the same direction as said first direction, and a plurality of resistor members extended in the same direction as said Second direction with the same intervals as said predetermined intervals of said second switch contacts between the first terminal members, said resistor members being supplied with voltages through said first terminal members; a resonant voltage change-over switch base plate consisting of an insulating plate having a hole therethrough and a second circular rotary contact arranged around the hole, a plurality of third switch contacts arranged around the periphery of the second circular rotary contact, and a plurality of second terminal members aligned in the same direction as said first direction with the same intervals as said predetermined intervals of said second switch contacts and electrically connected to said third switch contacts, respectively; a plurality of band change-over switches provided for respective said second switch contacts, each for selectively connecting the corresponding second switch contact to one of the band contacts aligned in the second direction in cooperating relation with said corresponding second switch contact so as to conduct the voltage applied to said one of the band contacts to the corresponding one of the first switch contacts for band changing-over; a mounting base plate, having a hole therethrough corresponding to the through-holes of said band-change-over switch base plate and resonant voltage change-over switch base plate, for mounting on one surface thereof said band change-over switch base plate on which said resistance base plate is mounted and on the other surface said resonant voltage change-over switch base plate; a plurality of slide members provided for respective said resistor members, each for taking out a predetermined voltage in accordance with the position thereof through sliding movement on the corresponding one of the resistor members; connecting means, perforating said resistance base plate, band change-over switch base plate and mounting base plate, for electrically connecting said slide members to said second terminal members, respectively, so as to conduct said predetermined voltages to respective said third switch contacts; a first rotary switch fixed to a rotary shaft inserted into said throughholes, for selectively connecting one of said first switch contacts to said first rotary contact so as to derive from the first rotary contact said voltage conducted to said one of the first switch contacts as a band change-over voltage to be applied to the variable tuning element; a second rotary switch, fixed to said rotary shaft, for selectively connecting one of said third switch contacts to said second rotary contact so as to derive from the second rotary contact said predetermined voltage conducted to said one of the third switch contacts as a resonant voltage to be applied to the variable tuning element for tuning; and driving means manually operable for driving said first and second rotary switches in a rotary movement for said selective connection.
 2. An electronic tuner according to claim 1, wherein said slide member comprises a threaded shaft and a slide contact supported on the shaft and movable on the shaft in accordance with the rotation of the shaft, and said connecting means comprises a U-shaped metal plate one end of which is fixed to said second terminal member and which is capable of rotatably supporting one end of the shaft at the bottom of the U-shape.
 3. An electronic tuner according to claim 1, wherein said insulating plate of said resistance base plate is provided with a plurality of slits for exposing said band contacts and second switch contacts for allowing said selective connections by said band change-over switches through said slits.
 4. An electronic tuner according to claim 1, wherein said driving means comprises at least one operation shaft movable along the axis thereof, a ratchet rotating in accordance with the movement in one direction of the operation shaft, and means for rotating said rotary shaft in accordance with the rotation of saiD ratchet. 